SUBSECTION 5D
HYDRAULIC COMPONENTS
INSTALLATION. In the event the valve was removed for
bench testing or if a new valve is being installed, proceed as
follows:
1. Line up the valve with the two holes on the mounting
panel. Install and tighten the two capscrews.
2. Remove all protective caps and connect the hydraulic
lines to the proper ports.
3. Connect the electrical adapters to the solenoid valve.
4. Start the engine, check for leaks, and test the valve for
proper operation.
ACCUMULATOR (45U47D1)
DESCRIPTION. This is a one gallon, nitrogen charged,
bladder type accumulator, which acts as a pressure stor-
age reservoir (see Figure 5D-2). It helps eliminate rapid
cycling of the unloading valve to prevent overheating of the
oil and it smooths out pressure surges in the system.
Hydraulic oil from the pump is supplied to the accumulator
until operating pressure is reached. This hydraulic oil in the
accumulator is supplied to the control valves the instant a
control valve is operated. When the accumulator is prop-
erly charged, the pressure gauge will show a gradual de-
crease in pressure when the control valves are actuated.
When minimum pressure is reached, the pump will again
charge the accumulator to operating pressure. The pres-
sure gauge will also show a gradual decrease in pressure
when the engine is turned off.
Figure 5D-2. Accumulator (45U47D1)
The most important function of the accumulator occurs in
the event of malfunction of the pump or the unloading valve
INSTALLATION. To install the accumulator, proceed as fol-
portion of the combination valve. If the pump or unloading
lows (see Figure 5D-1):
valve malfunctions, the stored oil in the accumulator will
enable the operator to make several clutch or brake en-
1. Line up the clamp and accumulator with the two holes in
gagements, thus allowing him to lower the load to the
the hydraulic units panel. Install and fully tighten the two
ground.
lockwashers and capscrews.
2. Remove the protective cap and connect the hydraulic
MAINTENANCE. This accumulator is considered non-re-
line to the accumulator.
pairable. If the accumulator is faulty, it may be due to loss of
precharge pressure or it may be due to a defective bladder or
3. Connect the battery ground cable. Start the engine and
housing. If the housing or bladder is faulty, the complete
observe the accumulator for leaks. Also, see that the
accumulator must be removed and replaced with a new ac-
accumulator charges to full operating pressure.
cumulator.
PRECHARGING PROCEDURE. There are two conditions
REMOVAL. To remove the accumulator, proceed as fol-
under which the accumulator precharge pressure should
lows (see Figure 5D-1):
be checked. The first is when a new accumulator is in-
stalled and the second is when it is found thet the reason for
a faulty accumulator is the toss of precharge pressure. The
1. See General Removal at the beginning of this section.
accumulator is precharged with oil pumped nitrogen, pre-
ferably, to 700 +25 psi at room temperature, 70F. A pre-
2. Disconnect the hydraulic line at the accumulator and po-
charging kit (45Z232) is available from Harnischfeger for
sition the line to avoid interference as the accumulator is re-
performing this operation.
moved. Cap the line to prevent the entry of contaminants.
3. Remove the two capscrews and lockwashers attaching
the accumulator and clamp to the hydraulic units panel.
When precharging the accumulator, use water
4. The accumulator can now be removed.
pumped, oil pumped or dry nitrogen only.
5D-3